System and method for depositing a material on a substrate

ABSTRACT

A method and apparatus for depositing a film on a substrate includes a plasma source positioned proximate to a distributor configured to provide a semiconductor coating on a substrate.

CLAIM FOR PRIORITY

This application is a divisional of application Ser. No. 12/320,060,filed Jan. 15, 2009, which claims priority under 35 U.S.C. §119(e) toProvisional U.S. Patent Application Ser. No. 61/021,148 filed on Jan.15, 2008, which is hereby incorporated by reference.

TECHNICAL FIELD

The present invention relates to photovoltaic device production.

BACKGROUND

In the manufacture of a photovoltaic device, semiconductor material isdeposited on a substrate. This may be accomplished by vaporizing thesemiconductor and directing the vaporized semiconductor toward asubstrate surface, such that the vaporized semiconductor condenses andis deposited on the substrate, forming a solid semiconductor film.

SUMMARY

A deposition system can include a distributor configured to provide asemiconductor coating on a substrate, a first power source configured toheat the distributor, and a plasma source positioned proximate to thedistributor, the plasma source including an electrode configured todrive the plasma source, wherein the electrode is electricallyindependent from the first power source.

In some circumstances, the system or method can include an additionalelectrode configured to bias the plasma source with respect to thesubstrate. An electrode can be a backcap over a distributor. Anelectrode can include a non-metallic material, such as carbon, forexample. In one example, an electrode can include graphite. An electrodecan be a spacer. An electrode can be a backcap. A spacer can be agraphite spacer. A backcap can be a graphite backcap.

In other circumstances, a distributor can include a pair of sheath tubesincluding a first sheath tube and a second sheath tube. An electrode canbe a spacer between a first sheath tube and a second sheath tube. Anelectrode can be a backcap over a first sheath tube and a second sheathtube.

In other circumstances, a distributor can include a pair of sheath tubesincluding a first sheath tube and a second sheath tube. An electrode canbe a conductor parallel to a first sheath tube and a second sheath tube.An electrode can be a backcap over a first sheath tube and a secondsheath tube.

In other circumstances, a distributor can be a pair of sheath tubesincluding a first sheath tube and a second sheath tube, and the plasmasource can include three graphite components electrically isolated fromone another. The first graphite component can be a first spacerseparating the first sheath tube from the second sheath tube. The secondgraphite component can be a second spacer separating the first sheathtube from the second sheath tube. The third graphite component can be abackcap over the first sheath tube and the second sheath tube. In othercircumstances, a system can further include an insulator between abackcap and each of the spacers.

In some circumstances, a distributor can include at least onedistribution hole configured to provide a semiconductor coating on asubstrate. A plasma source can be driven by direct current. A plasmasource can be driven by alternating current. A plasma source can bedriven by pulsed direct current. A plasma source can be driven byradiofrequency electrical excitation.

In certain circumstances, a system or method can include a conveyorconfigured to transport the substrate past the distributor. Adistributor can be positioned within a deposition chamber, thedeposition chamber including an entry through which the substrates to becoated are introduced into the deposition chamber; and the depositionchamber including an exit through which the coated substrates leave thedeposition chamber. A distributor can include a ceramic tube. Adistributor can include a mullite tube. A distributor can include aceramic sheath tube.

In other circumstances, a system or method can include a permeableheater positioned within the distributor. A plasma source can beconfigured to generate plasma in a region less than 10 centimeters froma substrate. A plasma source can be configured to generate plasma in aregion less than 7 centimeters from a substrate. A plasma source can beconfigured to generate plasma in a region less than 5 centimeters from asubstrate. A plasma source can be configured to generate plasma in aregion less than 2 centimeters from a substrate.

A method of depositing a material on a substrate can include providing afirst power source configured to heat a distributor, the distributorconfigured to deposit a semiconductor coating on a substrate, providinga plasma source including an electrode that is electrically independentfrom the first power source, and exciting a plasma within a volumeproximate to the distributor and proximate to the substrate.

The details of one or more embodiments are set forth in the accompanyingdrawings and the description below. Other features, objects, andadvantages will be apparent from the description and drawings, and fromthe claims.

DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic of system including a plasma source.

FIG. 1A is a schematic of system including a plasma source.

FIG. 2 is a schematic of system including a plasma source.

FIG. 3 is a schematic of system including a plasma source.

DETAILED DESCRIPTION

In general, a deposition system can include a distributor configured toprovide a semiconductor coating on a substrate, a first power sourceconfigured to drive a distributor, and a plasma source positionedproximate to the distributor, the plasma source including an electrodeconfigured to drive the plasma source, wherein the electrode iselectrically independent from the first power source. In somecircumstances, a system or method can include an additional electrodeconfigured to bias the plasma source with respect to the substrate. Anelectrode can be a conductor parallel to a distributor. An electrode canbe a backcap over a distributor. An electrode can include a non-metallicmaterial, such as carbon, for example. An electrode can includegraphite.

A distributor is an assembly, including a feed tube, a sheath tube, orboth, configured to deposit a material on a substrate through one ormore openings. A distributor can include a pair of sheath tubesincluding a first sheath tube and a second sheath tube. A sheath tubecan provide a spatial distribution of vapor through a plurality ofholes. A sheath tube can at least partially surround a feed tube such asa powder injection tube. A heater can be a tube provided to sheath afeed tube. A heater can, in turn, be sheathed by a sheath tube, therebyresulting in three substantially concentric tubes. The heater can be apermeable heater, which allows the material from a feeder tube topermeate through the heater and into a space between the heater and asheath tube.

Referring to FIG. 1, a distributor can be an assembly, which includes asheath tube 34 such as a ceramic sheath tube for example. In one aspect,a distributor can be an assembly including a sheath tube, a heater and afeed tube. A ceramic sheath tube 34 can sheath a heater 24, such aspermeable heater, which in turn, can sheath a feed tube. A sheath tube34 can include one or more distribution holes 36 configured to provide asemiconductor coating on a substrate 8. A plasma source can include anelectrode configured to generate a plasma. A system can also include anadditional electrode configured to bias the plasma source with respectto the substrate 8. In certain circumstances, as shown in FIG. 1A, adistributor can include a pair of sheath tubes 34, 34 a. In oneembodiment, an electrode can be a spacer 5 between a first sheath tube34 and a second sheath tube 34 a. A spacer 5 can include a graphitecross-rod electrode. A spacer 5 can include a non-metallic material,such as carbon, or other material that is resistant to corrosion. In oneembodiment, a spacer 5 can be a graphite spacer. An additional electrodecan be a backcap 4 over sheath tubes 34, 34 a. A backcap 4 can be agraphite backcap. An insulator 6 can be positioned between the spacer 5and the graphite backcap 4.

FIG. 2 is a view taken across the cross-section A-A of FIG. 1A. FIG. 1Ais a cross-section view at line B-B of FIG. 2. Referring to FIG. 2, asystem can include a distributor power source 100 configured toresistively heat the distributor assembly 30, and a first plasma source4 (referenced in FIG. 1A as a backcap 4) and second plasma source 5(referenced in FIG. 1A as spacer 5) positioned proximate to thedistributor assembly and proximate to the substrate 8. Second plasmasource can include a graphite cross-rod electrode 5 a. In thisconfiguration, a first plasma source 4 and a second plasma source 5 arein parallel. The first or second plasma source 4, 5 can excite a plasmawithin a volume 40 within a distributor and proximate to the substrate.The plasma source 5 can include an electrode and a power source 10configured to drive the electrode. The plasma source 4 can furtherinclude an additional electrode, and an additional power source 20configured to bias the plasma with respect to the substrate 8. Thedistributor can include a sheath tube 34, a permeable heater 24 sheathedby the sheath tube, and a feed tube sheathed by the permeable heater. Adistributor can include one or more distribution holes 36 configured toprovide a semiconductor coating on a substrate. In one embodiment, anelectrode can be a spacer between a first sheath tube and a secondsheath tube, or a cross-rod electrode 5 a, for example. A spacer caninclude a non-metallic material, such as carbon. In one embodiment, aspacer can be a graphite spacer. An additional electrode can be abackcap 4 over a first sheath tube and a second sheath tube. A backcapcan be a graphite backcap. An insulator 6 can be positioned between thespacer and the graphite back cap.

FIG. 3 is another embodiment showing a system including a distributorpower source 100 configured to resistively heat the distributor assembly30, and a first plasma source 4 and second plasma source 5 positionedproximate to the distributor assembly and proximate to the substrate 8.The first or second plasma source 4, 5 can excite a plasma within avolume 40 within a distributor and proximate to the substrate. Theplasma source 5 can include an electrode and a power source 10configured to drive the electrode. The plasma source 4 can furtherinclude an additional electrode, and an additional power source 20configured to bias the plasma with respect to the substrate 8. Thedistributor can include a sheath tube 34, a permeable heater 24 sheathedby the sheath tube, and a feed tube sheathed by the permeable heater. Adistributor can include one or more distribution holes 36 configured toprovide a semiconductor coating on a substrate. In one embodiment, anelectrode can be a spacer between a first sheath tube and a secondsheath tube, or a cross-rod electrode, for example. A spacer can includea non-metallic material, such as carbon. In one embodiment, a spacer canbe a graphite spacer. An additional electrode can be a backcap 4 over afirst sheath tube and a second sheath tube. A backcap can be a graphitebackcap. An insulator 6 can be positioned between the spacer and thegraphite back cap.

Prior methods and systems of depositing a material do not involveintentional plasma processing. The system and method described hereinincludes exciting a plasma within a volume within a distributor andproximate to the substrate. The plasma can be very useful for addingenergy into the deposition source vapor. This added energy can break updimers such as Te₂ or S₂ and thereby altering film growth. The monomersTe or S are expected to be more reactive and exhibit different surfacemobilities and crystal growth attributes. The plasma can provide chargedspecies to the growing surface that would alter film growth. The plasmacould also break up other dimers such as N₂, P₂, P₄, As₂, and Sb₂(dopants) whose incorporation in thermal vapor transport depositiontends to be relatively low. Breaking up dopant dimers can greatlyenhance incorporation probabilities. The plasma can also supply excitedmetastable neutrals such as He* or Ar* or O2* that can deliver extra andcontrollable energy to the growing surface.

Various plasma configurations can be used. For example the plasma sourcecan be driven by direct current (dc), alternating current (ac), pulseddirect current, or radiofrequency (rf) electrical excitation. Theelectrical power supply is electrically connected to the electrode,wherein the electrode is a component of the plasma source. The electrodeconfiguration could be diode or triode. The plasma could be biased (ac,pulsed dc, or rf) with respect to the substrate which would be a virtualground. Various geometries of electrodes are possible, and variouspressures can be applied. For example, in certain circumstances, apressure of 0.1-5.0 Torr can be applied.

In some circumstances, a two-tube distributor configuration as shown inFIGS. 1A, 2 and 3, can be quite advantageous for plasma generation. Theconfiguration including a graphite backcap, two mullite tubes and twographite hourglass end spacers, define five sides of a volume of adistributor assembly containing the deposition vapor with the remainingside an outlet pointed toward the substrate. In this configuration,three graphite components can be electrically isolated from one anotherand used as electrodes. In this way, the electrodes are completelyseparated and independent from the power driving the resistive heatingof the permeable SiC heater tubes, 2. Because the plasma source ispowered independent of the distributor's power source, the plasma sourcecan be operated at any advantageous condition from very weak to highlyexcited. In certain circumstances, a system can include two powersupplies for the plasma sources. A power source can be used to drive theelectrode to generate the plasma, while an additional power source canbe used to bias the plasma with respect to the substrate. The powersource configured to drive the electrode to generate the plasma can beindependent of the power source used to drive the distributor assembly.A plasma source can be configured to generate plasma in a region lessthan 7 centimeters from a substrate. A plasma source can be configuredto generate plasma in a region less than 5 centimeters from a substrate.A plasma source can be configured to generate plasma in a region lessthan 2 centimeters from a substrate.

Various distributor assembly systems and methods for depositing asemiconductor film on a glass substrate are described, for example, inU.S. Pat. No. 5,945,163, U.S. Pat. No. 6,037,241, and U.S. applicationSer. No. 11/380,073, the disclosures of which are herein incorporated byreference in its entirety.

In general, a method and system for depositing a semiconductor materialon a substrate includes introducing a material and a carrier gas into adistributor assembly having a heated first chamber to form a vapor ofthe material. The material can be a powder, for example, a powder of asemiconductor material. The carrier gas and vapor are then directedthrough a series of successive heated chambers to form a uniformvapor/carrier gas composition. The uniformity of the gas composition canbe provided by flow and diffusion of the vapor and gas incident topassing the vapor and gas through a plurality of chambers of thedistributor assembly. After the composition has become uniform, it isdirected out the distributor assembly and towards a substrate, causing afilm to be formed on a surface of substrate. The substrate can be aglass substrate or another suitable substrate such as polymer substratehaving a surface suitable for forming a uniform film. The film can be asemiconductor composition. The vapor and carrier gas composition may bepassed through a filter after being introduced into the distributorassembly in order to ensure that solid particles of that material arenot directed toward the substrate. Advantageously, the method and systemfor depositing a semiconductor material provides a semiconductor filmwith improved film thickness uniformity and grain structure uniformity.

A deposition system can include a housing defining a processing chamberin which a material is deposited on a substrate. A substrate can be aglass sheet. A housing can include an entry station and an exit station.The housing can be heated in any suitable manner such that itsprocessing chamber can be maintained at a deposition temperature. Thedistributor temperature can be about 500 degrees to about 1200 degreesC. A substrate can be heated during the processing to a substratetemperature. The substrate temperature can be 200 degrees to 650 degreesC. Substrate 400 can be transported by any appropriate means such asrollers 230, or a conveyor belt, preferably driven by an attachedelectric motor. Systems and methods for transport are described, forexample in U.S. application Ser. Nos. 11/692,667, 111918,009 and11/918,010, which are hereby incorporated by reference in theirentirety.

A distributor can be an assembly which includes a feed tube and amaterial supply, which can include a hopper containing a powder and acarrier gas source containing an appropriate carrier gas. Powder cancontact carrier gas in the feed tube, and both carrier gas and powdercan be introduced into a distributor assembly.

After carrier gas and powder are introduced into the distributorassembly, the powder is vaporized and directed through distributorassembly along with carrier gas in such a manner that carrier gas andthe vapor are mixed to form a uniform vapor/carrier gas composition. Theuniform vapor/carrier gas composition is then directed out ofdistributor assembly toward substrate. The lower temperature of asubstrate compared to the temperature in a distributor assembly in orderto maintain the material in vapor phase, causes condensation of thevapor on a surface of substrate, and the deposition of a film, which hasa substantially uniform thickness and a substantially uniform structuredemonstrating a uniform crystallization and a substantial absence ofparticulate material, such as unvaporized powder.

The exit point of the semiconductor vapor from distributor assembly canbe spaced from substrate at a distance in the range of about 0.5 toabout 5.0 cm to provide more efficient deposition. While greater spacingcan be utilized, that may require lower system pressures and wouldresult in material waste due to overspraying. Furthermore, smallerspacing could cause problems due to thermal warpage of substrate duringconveyance in the proximity of the higher temperature distributorassembly. A substrate can pass proximate to the point where thesemiconductor vapor exits the distributor assembly at a speed of atleast about 20 mm per second to about 60 mm per second.

In performing the deposition, successful results have been achievedusing cadmium telluride and cadmium sulfide as the material. However, itshould be appreciated that other materials can be utilized which includea transition metal (Group IIB) and a chalcogenide (Group VIA). It shouldbe further appreciated that additional materials that can be utilized toform a semiconductor film have many useful applications (such as themanufacture of photovoltaic devices) and may be used with the systemsand methods described herein. Also, dopants may be useful to enhance thedeposition and properties of the resulting film.

Use of a processing system to perform the method has been performed witha vacuum drawn in the processing chamber 250 to about 0.1 to 760 Torr.The processing system can include a suitable exhaust pump for exhaustingthe processing chamber of the housing both initially and continuouslythereafter to remove the carrier gas.

The carrier gas supplied from the source can be helium, which has beenfound to increase the glass temperature range and the pressure rangethat provide film characteristics such as deposition density and goodbonding. Alternatively, the carrier gas can be another gas such asnitrogen, neon, argon or krypton, or combinations of these gases. It isalso possible for the carrier gas to include an amount of a reactive gassuch as oxygen or hydrogen that can advantageously affect growthproperties of the material. A flow rate of 0.3 to 10 standard liters perminute of the carrier gas has been determined to be sufficient toprovide the material flow to distributor assembly for deposition on asubstrate.

It should be recognized that multiple material supplies having multiplehopper and multiple carrier gas sources may introduce carrier gas andmaterial into the distributor assembly. The distributor shown in FIGS. 1and 2 is shown for the sake of clarity. Alternate embodiments of amaterial supply can be used. For example, a vibration introduced by avibratory feeder can cause powder to incrementally move from a hopperinto an inclined passage. In this manner, powder is introduced into afeed tube, along with carrier gas from a carrier gas source.Alternatively, a semiconductor film may be deposited on adownward-facing surface of a substrate.

Various embodiments of a distributor assembly are also described below.One embodiment of a distributor assembly is described with reference toits internal components. As described above, a carrier gas and materialare introduced into a distributor assembly which can include a tube,which can be formed from mullite. A heater can be formed from graphiteor silicon carbide (SiC), and can be resistively heated by applying acurrent across a heater tube.

A distributor can include a sheath tube, which has a least onedistribution hole configured to deposit semiconductor material on asubstrate. Distribution holes can have a diameter of about 1 mm to about5 mm. The number of distribution holes included in distributor assemblycan be varied as required, and can be spaced from about 19 mm to about25 mm apart, for example. The uniform vapor/carrier gas composition canbe directed into a nozzle formed by a graphite cradle, after which thevaporized semiconductor is deposited on an underlying substrate, whichcan be a glass sheet substrate. Directing the uniform vapor/gascomposition streams emitted from a distribution hole into a cradledisperses the uniform vapor/gas composition and further increases itsuniformity of composition, pressure and velocity in preparation fordeposition on underlying substrate. The proximity of a substrate to anozzle increases the efficiency of depositing the film by reducing theamount of material wasted.

A sheath tube can be formed from mullite. During the passage through aheater tube and into and within the sheath tube, the irregular flow ofvapor and carrier gas can result in continuous mixing and diffusion ofthe vapor components and carrier gas to form a uniform vapor/carrier gascomposition. The interior of a sheath tube can also include athermowell, which can be formed from aluminum oxide and can have anouter diameter of about 5 mm to about 10 mm, for monitoring thetemperature of distributor assembly.

The uniform vapor/carrier gas composition can be directed within theinterior of a sheath tube or tubular sheath, dispersing the streams ofvapor and carrier gas directed from outlets and increasing theuniformity of composition, pressure and velocity of the vapor andcarrier gas. The uniform vapor/carrier gas composition can be directedtoward a slot or distribution hole, which can be located on a side ofsheath tube substantially opposite from the outlets to provide a lengthyand indirect path for the vapor and carrier gas, thereby promotingmaximum mixing and uniformity of the vapor/carrier gas composition. Theuniform vapor/carrier gas composition can be directed out of outersheath tube through a distribution hole and can be deposited on asurface of underlying substrate.

An alternative embodiment of a distributor assembly includes a permeableheater. A powder and a carrier gas are introduced into a permeableheater or a heated tube, which is heated resistively. The resistiveelectrical path can be provided by a tubular center electrode, which canbe formed from graphite. A heated tube can be permeable and made fromSiC. Also contained within the interior of a heated tube can be athermowell for monitoring the temperature of a heated tube.

The heat provided from a resistively heated tube causes the powder tovaporize inside heated tube, after which the resulting vapor and carriergas permeate the walls of heated tube and are directed to the interiorof surrounding sheath tube, which can be composed of mullite. The powderthat is not vaporized does not permeate the walls of heated tube. Asurrounding sleeve can be oriented inside a larger-diameter outer sheathtube, with portions of a tubular center electrode separating surroundingsleeve from outer sheath tube, which, like surrounding sleeve can bemade from mullite. The vapor and carrier gas can be prevented fromescaping the interior of surrounding sleeve by a stopper sleeve, whichcan be made of ceramic tape packing. The vapor and carrier gas can bedirected into a passageway formed in a tubular center electrode. As thevapor and carrier gas travel through distributor assembly, andpassageway in particular, the irregular flow pattern causes the vaporand carrier gas to mix and diffuse into a substantially uniformvapor/carrier gas composition.

After the vapor/carrier gas uniform composition is directed into aheated tube, it can travel within and along a heated tube, continuouslyremixing the vapor/carrier gas composition. The uniform vapor/carriergas composition is directed out of the heated tube into the interior ofsheath tube through a plurality of outlets, which can be holes drilledin a line along a portion of the length of one side of the heated tube.As with previous embodiments, after traveling through outlets, thevapor/carrier gas composition is directed within the sheath tube,dispersing the streams of vapor/carrier gas composition directed throughoutlets and further promoting vapor/carrier gas uniformity ofcomposition, pressure and velocity. The vapor/carrier gas composition isthen directed toward a slot or distribution hole, which is preferablyprovided on a side of outer tubular sheath substantially oppositeoutlets to maximize the path length of the vapor/carrier gas compositionand resulting uniformity thereof. Finally, the substantially uniformvapor/carrier gas composition is directed out a slot or distributionhole (which can be provided along the entire length of outer tubularsheath) toward underlying substrate so that a film may be depositedthereon.

In another embodiment, powder and carrier gas can first be directed intoa filter tube positioned inside a heater or heater tube. The heater tubeheats a filter tube to a temperature sufficient to vaporize the powderinside filter tube. The filter tube can also be resistively heated andcan be permeable to the vapor, so the vapor and carrier gas permeatefilter tube and are directed into heater tube. A filter tube can beformed from SiC.

As vapor and carrier gas permeate into the heater tube from the filtertube, the mixed vapor and carrier gas are directed out of the heatertube through an outlet, which can be a single hole or opening locatednear one end of heater tube, and which can have a diameter of about 10mm to about 15 mm, for example. The vapor and carrier gas can bedirected through an outlet, which causes the vapor and carrier gas tocontinue to mix while entering the interior of a manifold, which can beformed from graphite, and which can have an outer diameter of about 75mm to about 100 mm (preferably about 86 mm), and an inner diameter ofabout 60 mm to about 80 mm (preferably about 70 mm). The flow of thevapor and carrier gas within the manifold causes the vapor and carriergas to continue to mix and form a uniform vapor/carrier gas composition.The vapor and carrier gas can be directed from an outlet on one side ofheater tube around heating tube inside the manifold to a plurality ofdistribution holes positioned in a line along the length of manifold ona side of a manifold substantially opposite the side of heater tubewhere drilled hole is located. A thermowell can also be providedproximate to heater tube in order to monitor the temperature ofdistributor assembly.

In another embodiment, an additional feed tube and material source maybe provided at an opposite end of distributor assembly.

In an alternate embodiment, a powder and a carrier gas are directed intothe interior of first heater tube via a feed tube. The first heater tubecan be resistively heated to a temperature sufficient to vaporize thepowder and is permeable to the resulting vapor and the carrier gas, butimpermeable to the powder. Consequently, any powder that is notvaporized is unable to pass from the interior of first heater tube. Thefirst heater tube can be formed from SiC.

After the powder is vaporized to form a vapor, the vapor and carrier gaspermeate the walls of first heater tube and are directed to the spacebetween first heater tube and first tubular sheath, which can be formedfrom mullite, graphite, or cast ceramic. Passage within a tubular sheathcauses the vapor and carrier gas to mix to form a uniform vapor/carriergas composition. The uniform vapor/carrier gas composition is directedthrough a space formed in the tubular sheath toward an underlyingsubstrate onto which the vapor is deposited as a film.

The embodiments described above are offered by way of illustration andexample. It should be understood that the examples provided above may bealtered in certain respects and still remain within the scope of theclaims. It should be appreciated that, while the invention has beendescribed with reference to the above preferred embodiments, otherembodiments are within the scope of the claims.

1-28. (canceled)
 29. A method of depositing a material on a substratecomprising: providing a first power source configured to heat adistributor, the distributor configured to deposit a semiconductorcoating on a substrate; providing a plasma source including an electrodethat is electrically independent from the first power source; andexciting a plasma within a volume proximate to the distributor.
 30. Themethod of claim 29, wherein the plasma source further comprises anadditional electrode configured to bias the plasma with respect to thesubstrate.
 31. The method of claim 29, wherein the electrode includes anon-metallic material.
 32. The method of claim 29, wherein the electrodeincludes carbon.
 33. The method of claim 29, wherein the electrode is abackcap over the distributor.
 34. The method of claim 33, wherein thebackcap is a graphite backcap.
 35. The method of claim 29, wherein thedistributor includes a pair of sheath tubes including a first sheathtube and a second sheath tube.
 36. The method of claim 35, wherein theelectrode is a spacer between the first sheath tube and the secondsheath tube.
 37. The method of claim 36, wherein the spacer is agraphite spacer.
 38. The method of claim 35, wherein the electrode is abackcap over the first sheath tube and the second sheath tube.
 39. Themethod of claim 29, wherein the distributor includes a pair of sheathtubes including a first sheath tube and a second sheath tube, and theplasma source includes three graphite components electrically isolatedfrom one another.
 40. The method of claim 39, wherein the first graphitecomponent is a first spacer separating the first sheath tube from thesecond sheath tube, the second graphite component is a second spacerseparating the first sheath tube from the second sheath tube, and thethird graphite component is a backcap over the first sheath tube and thesecond sheath tube.
 41. The method of claim 40, further comprising aninsulator between the backcap and each of the spacers.
 42. The method ofclaim 29, wherein the distributor includes at least one distributionhole configured to provide a semiconductor coating on a substrate. 43.The method of claim 29, wherein the plasma source is driven by directcurrent.
 44. The method of claim 29, wherein the plasma source is drivenby alternating current.
 45. The method of claim 29, wherein the plasmasource is driven by pulsed direct current.
 46. The method of claim 29,wherein the plasma source is driven by radiofrequency electricalexcitation.
 47. The method of claim 29, further comprising a conveyorconfigured to transport the substrate past the distributor.
 48. Themethod of claim 29, wherein the distributor is positioned within adeposition chamber, the deposition chamber including an entry throughwhich the substrates to be coated are introduced into the depositionchamber; and the deposition chamber including an exit through which thecoated substrates leave the deposition chamber.
 49. The method of claim29, wherein the distributor includes a ceramic tube.
 50. The method ofclaim 29, wherein the distributor includes mullite tube.
 51. The methodof claim 29, wherein the distributor includes a ceramic sheath tube. 52.The method of claim 29, further comprising a heater positioned withinthe distributor.
 53. The method of claim 29, wherein the plasma sourceis configured to generate plasma in a region less than 10 centimetersfrom a substrate.
 54. The method of claim 29, wherein the plasma sourceis configured to generate plasma in a region less than 7 centimetersfrom a substrate.
 55. The method of claim 29, wherein the plasma sourceis configured to generate plasma in a region less than 5 centimetersfrom a substrate.
 56. The method of claim 29, wherein the plasma sourceis configured to generate plasma in a region less than 2 centimetersfrom a substrate.